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Tamasgavabari R.,Metallic Materials Research Center | Jafarzadeh K.,Metallic Materials Research Center | Madanipoor M.,Iranian Mineral Processing Research Center | Badri H.,Metallic Materials Research Center
Corrosion Engineering Science and Technology | Year: 2014

In this paper, the effect of surface oxidation on corrosion behaviour of Co-20?8Ni-6Al-10Cu-11Fe alloy in molten cryolite is investigated. The samples were produced by casting and then were oxidised at 1000°C for 10, 30 and 70 h respectively. The oxide layers were studied by scanning electron microscope (SEM) and X-ray diffraction (XRD). To determine the corrosion behaviour of the oxidised samples, they were exposed to molten cryolite at 930°C for 20 h. After corrosion, the samples were studied by SEM. The results showed that all the samples corroded, but the sample oxidised for 70 h, was more stable than the other and the other one that oxidised for 10 h, corroded severely. Source

Hassan J.,University of Tehran | Shamsipur M.,Razi University | Karbasi M.-H.,Iranian Mineral Processing Research Center
Microchemical Journal | Year: 2011

A new and simple method was developed for preconcentration trace amount of gold in aqueous and mineral samples. The method was based on the sorption of gold on granular activated carbon (AC) in acidic medium (hydrochloric acid) and subsequently direct determination by graphite furnace atomic absorption spectrometry (GFAAS). A small particle of adsorbent was delivered to small volume of sample. After extraction, AC removed and analyzed directly by GFAAS. Several factors influencing the extraction efficiency, such as the hydrochloric acid concentration, sample volume and extraction time were studied as well as effect of potential interfering ions. The preconcentration factor 50 was obtained. The limit of detection (LOD) of gold in water and soil samples was 0.007μgL-1 and 0.9ngg-1, respectively. The proposed method was applied successfully to the determination of trace amount of gold in environmental and geological samples. In order to validate the developed method, two certified reference materials: Platinum Ore (SARM-7B) and Copper Ore Mill Heads (No. 330) were analyzed and the determined values obtained were in good agreement with the certified values and recovery was obtained in the range of 80-118%. The relative standard deviations (RSD) for the spiking levels of 0.5μgL-1 in the real samples was 4%, (n=15). © 2011 Elsevier B.V. Source

Hassan J.,University of Tehran | Farahani A.,Iranian Mineral Processing Research Center
Chromatographia | Year: 2011

A fast and effective sample cleanup procedure for the quantification of polycyclic aromatic hydrocarbons (PAHs) in fish samples is presented. The procedure involved extraction of fish samples using acetonitrile and cleanup by an automated gel-permeation chromatography (GPC) following liquid-liquid partition into n-hexane. The extracted samples were analyzed by gas chromatography-mass spectrometry (GC-MS). Electron ionization was employed in a single analysis for the determination of PAHs in the selected ion monitoring mode. Three different solvents were studied for the extraction step: acetonitrile/n-hexane, methanol/n-hexane and acetone/n-hexane. The best solvent was found to be acetonitrile/n-hexane. The cleanup technique resulted in a good separation of analytes from co-extractive matrix compounds. © 2011 Springer-Verlag. Source

Zolghadri M.,Tarbiat Modares University | Ghaffari A.,Iranian Mineral Processing Research Center | Parian M.A.,Tarbiat Modares University | Haghi H.,University of Tehran
26th International Mineral Processing Congress, IMPC 2012: Innovative Processing for Sustainable Growth - Conference Proceedings | Year: 2012

MIBC and sodium metasilicate are used as a frother and a dispersant in coal flotation respectively. In order to study interaction between them, flotation experiments were performed on fine coal (<150 microns). It was found that if the frother (MIBC) dosage is in excess of a certain limit, it has an activation effect on the gangue minerals associated with coal. In addition, it was found that however sodium metasilicate can disperse clay slimes eliminating slime coating, but in the case of excess dosage, could intensify activation effect of MIBC, which is undesirable in coal flotation. Source

Mansouri N.,Islamic Azad University at Tehran | Rikhtegar N.,Islamic Azad University at Tehran | Panahi H.A.,Islamic Azad University at Central Tehran | Atabi F.,Islamic Azad University at Tehran | Shahraki B.K.,Iranian Mineral Processing Research Center
Environment Protection Engineering | Year: 2013

The characterization and porous structure of raw and modified clinoptilolite as a sorbent has been investigated by nitrogen adsorption, X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, differential thermal analysis, scanning electron microscopy and atomic force microscopy methods. The nitrogen adsorption data revealed that the total pore volume and specific surface area were increased after modification. The nitrogen adsorption was used to determine percent of mesoporosity. The TG data show that 14 wt. % of clinoptilolite is lost after heating up to 1200 °C. Two types of porosities - primary porosity (microporosity) and secondary one (meso- and macropo-rosity) have been observed. Source

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